Revert for_api value on yes_no champs

app/models/champs/checkbox_champ.rb

@@ -1,19 +1,9 @@
-class Champs::CheckboxChamp < Champ
-  def search_terms
-    if value == 'on'
-      [libelle]
-    end
-  end
-
-  def to_s
-    value == 'on' ? 'Oui' : 'Non'
+class Champs::CheckboxChamp < Champs::YesNoChamp
+  def true?
+    value == 'on'
   end
 
   def for_export
-    value == 'on' ? 'on' : 'off'
-  end
-
-  def for_api
-    value == 'on' ? 'on' : 'off'
+    true? ? 'on' : 'off'
   end
 end

app/models/champs/yes_no_champ.rb

@@ -1,6 +1,6 @@
-class Champs::YesNoChamp < Champs::CheckboxChamp
+class Champs::YesNoChamp < Champ
   def search_terms
-    if value == 'true'
+    if true?
       [libelle]
     end
   end
@@ -13,13 +13,13 @@ class Champs::YesNoChamp < Champs::CheckboxChamp
     processed_value
   end
 
-  def for_api
-    processed_value
+  def true?
+    value == 'true'
   end
 
   private
 
   def processed_value
-    value == 'true' ? 'Oui' : 'Non'
+    true? ? 'Oui' : 'Non'
   end
 end